DE 197 11 382 C2 discloses a hydraulic vehicle brake of this type.
In the prior art brake, the brake is applied in the parking brake mode by means of a two-stage gear driven by an electric motor. A parking brake operation is effected by way of energizing the electric motor, while the spring element of the energy accumulator is preloaded in addition. A reversed rotation of the electric motor is necessary for the release operation of the parking brake.
Also, combined service and parking brakes are known in the art, wherein there is provision of a hydraulic actuating device for service brake operations and mechanically actuated locking devices as a parking brake. However, these assemblies suffer from the shortcoming that an additional brake cable must be provided apart from the hydraulic supply line for each brake. The result is an increased expenditure in material and manufacture. In addition, the brake cable can be mounted to the vehicle only after installation of the brake. This assembly is usually not carried out by a particularly competent brake manufacturer, but is generally done by the vehicle manufacturer. Beside the disadvantage incurred by an increase assembly effort, the vehicle manufacturer must additionally bear the risk of a faulty assembly.
Further, German published application DE 42 05 590 C1 discloses a brake system wherein a service brake operation is carried out hydraulically and a parking brake operation is assisted by an electromotive adjusting apparatus. An electromotive adjusting apparatus of this type, which acts directly on the position of the brake pedal, admittedly, relieves the driver in terms of the force effort to be made in a parking brake operation, yet entails additional structural effort. The result is that additional costs are incurred.